Phoenix requires specific span attributes for cost tracking: llm.token_count.prompt, llm.token_count.completion, llm.token_count.total, llm.model_name, and llm.provider. If any are missing or mismatched, cost will not be calculated鈥攅ven if token counts are present. Also, the model name and provider in your traces must match the patterns in your model pricing settings, including any custom entries you鈥檝e added. Regex mismatches or typos in the model name pattern can prevent cost calculation. Double-check that all required attributes are present in your spans and that your model pricing configuration matches the trace data exactly. For more, see the <https://arize.com/docs/phoenix/tracing/how-to-tracing/cost-tracking|cost tracking documentation> and <https://github.com/Arize-ai/phoenix/issues/8465|related troubleshooting discussion>.
If all attributes and pricing settings are correct but cost is still missing, inspect the raw span data in Phoenix to confirm the attributes are present and correctly formatted. Some instrumentations or LLM providers may not emit all required fields, or may use slightly different model names. Upgrading to the latest instrumentation packages and ensuring your model pricing regex matches the exact model name in the trace often resolves the issue. Would you like a step-by-step checklist or code example for debugging this further?
Sources:
- <https://arize.com/docs/phoenix/tracing/how-to-tracing/cost-tracking|Cost Tracking - Phoenix>
- <https://github.com/Arize-ai/phoenix/issues/8465|Phoenix GitHub Issue: Cost not shown with DSPy instrumentation>
